Hi Dominic,
Sounds as if you have ingress of air somewhere up at the boiler. Try checking all seals, on the pump etc, and joints.
A tiger loop would be a sinple way out, but they shouldn't really be installed in beside the burner, as the nature of the product is to allow the oil to 'air' but also allows oil vapour out so there is always a fire risk.
If the burner is left off (with oil all the way up that see-through pipe) does it fall away after a time, if so I would look to the hose connections as the may be allowing air to pass.
Make sure all fittings and bleed screw are thightened.
Why would this happen after 8 years of happy running, well kero can be quite hard on rubber seals (o rings) and may have well got to the point where one is passing
T
April 2008
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